Microstructure evolution in titanium carbide with different stoichiometry under 3 MeV Au2+ ion irradiation

Titanium carbide (TiC) with the merits of stability and corrosion resistance has been regarded as promising structural material candidate for advanced nuclear reactors. The effects of deviation in carbon stoichiometry and local ordering of carbon vacancies on the irradiation-induced microstructure evolution of TiC _x ( x = 0.62–0.98) were targeted. 3 MeV Au ²⁺ ion irradiation at room temperature (RT) was conducted over a series of ion fluences ranging from 1 × 10 ¹⁴ to 2 × 10 ¹⁶ ions cm ^-2, together with grazing incidence X-ray diffraction (GIXRD) and transmission electron microscopy (TEM). No amorphization was traced for titanium carbide ceramics with different stoichiometry irradiated at doses up to ∼70 displacements per atom (dpa). Substoichiometric titanium carbides exhibited excellent lattice expansion resistance compared to near stoichiometric one beyond a dose of ∼30 dpa. In addition, irradiation-induced two ordered phases and twins were observed. Local ordering of C vacancies benefits the accommodation, annihilation of irradiation induced defects, which enhances the tolerance of irradiation-induced amorphization of titanium carbide ceramics. This work provides a comprehensive understanding of microstructure evolution in titanium carbide with different stoichiometry, which facilitates the application of titanium carbide ceramics as advanced reactors cores concepts.